<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    /* is选择器根据的是里面最高的权重来计算的 */
    .box > :is(h1, h2, h3, h4, h5) {
      color: pink;
    }
    .container .box:is(.box, #baz) {
      color: red;
    }
  </style>
</head>
<body>
  <div class="box">
    <h1 class="title">h1</h1>
    <h2 class="title">h2</h2>
    <h3 class="title">h3</h3>
    <h4 class="title">h4</h4>
    <h5 class="not">h5</h5>
  </div>

  <!-- 增加一些属性 -->
   <div class="container">
      <p class="box">自动给css增加类名</p>
   </div>
</body>
</html>